A characteristics approach to swept shock-wave/boundary-layer interactions

A theoretical study was made of shock/boundary-layer interaction in three dimensions. Using the smallperturbation approach of the Lighthill triple-deck model, the nature of the propagation of spanwise disturbances in swept interactions was analyzed for nonseparating flows. It was found that, to a first approximation, disturbances propagate upstream along shock/boundary-layer interaction characteristics, the direction of which is determined by the properties of the boundary layer and the mainstream. For a semi-infinite swept interaction, the analysis predicts that the flow adopts a generally cylindrically symmetric form and that the end effects are manifested by termination of the upstream flow pattern along a shock/boundary-layer interaction characteristic. Predicted pressure distributions are found to be consistent with experimental results for glancing shock interactions.